Vibration amplitude and center of oscillation indicator



Aug. 31, 1943- l. A. WEAVER ETAL 2,323,114

VIBRATION AMPLITUDE AND CENTER OF OSCILLATION INDICATOR Filed Jan. 5,1942- 3 Sheets-Sheet 1 Aug. 31, 1943. i. A. WEAVER ETAL 2,328,114

VIBRATION AMPLITUDE AND CENTER OF OSCILLATION INDICATOR I Filed Jan. 5,1942 s Sheets-Sheet 2 6? wZz-w a Aug- 19430 I, A. WEAVER ET AL 2,323,114

VIBRATION AMPLITUDE AND CENTER OF OSCILLATION INDICATOR 121" 'EQBNWLHTUDE AND CENTER 6 55 SQE$ATKGN DIDICATOR {it Wezwez: em! Ctyde H.Phelps, sprfiekfi m te Weaver Manufacturing @QBELH meme-field, m, a.cerpomtien ef mete t, 1M2, Serial No. 425m {CL 73M 53) Inasmuch the tinvention mevicies means. to indieete center e-f vibmtien amplitude e1."eseil lei u eplies a effected by varietie -f reteztiezr. e m w ofunbalance, ee oxen remaining 60 stem; while gamut, spec-met: eheve, isa, variable speed amt weight Time invention per" capable e-f denotingthe e, retatiug 12042 and vibmticm, when the med a in, in, ture whereinthere is, ta eecilletien th LiE-JVGZV eueh that the m we. be 'reteter'eds whim me be e eriticei er 2%.3076' "whim test e the unique contactWet; is eubstentieiiy etantaneoue in we ei iudieating A eel te exactcenter yositieu eheve referrer}; t0, e116? 1e t'liibti adjusting a,centect se assembly at the mung? test u ee 'eetiun 2 vice, carrying 33simple mwutablte yeeistence u the exact amplitude ef eseilletien can beim' b igned metmfiy e Ct? e eet eff eated in thousandthe of imam-highlymagni 0f we in one eez't'eeeietcz t upeu on theelectric-metereznpleyeei, desired, 01 of the dlcated directly in weight-waits from aru 9 The instant invention pa'e'vi F:-

semi '25 and as this 'ainciicsttieu manually in eperatien,

exact mechanism to in be H emzmtuce of the meter shews the value afterthe rotation such viemtien am; the e?" eentez" thereef, whieh stopped.

meene fer euli" me be test, the I To enable these eequeinteel with thisart te remeeiiel Weight 3641 eat be buiemee understand the invemtten inits various aspects mtien, as wet; 2m

eat ng the m and details, a present Y e'eferred embodiment e1 gumrueeizzie-u e2? eeint e2 of smell the same has been illustrated in theece0mpany= wrreetie e11 weight. ing drawinge, in which like referencenumerals have been used t0 designate the same throughout the severeiviews.

in these airawz'ugs- Fi ure 1 is a plan View e1 the genera] stzuctme;Figure 5311s 8131 emit elevetien uf the'eame; Figure 3 is aneie'trtttieu and partial sectien uiitude oi Wteetion and the sen eeix mwe L "hrough the variable ceutezet tieviee; tion thereef at the pointeff e1 1 Figure 4 is evertteei eectiem through web. can new device teany b-alaucingmmehme where such tact mechanism em line tof Figure 3;cenditions exist, after winch, eaieule Figure 5 illustrates the emieeeef the indextion or additional correctional er eempensatmg wheel as laidout fiat; a paratus and through the meme e1 in Figure 6 skews eue termef circuit cennectiens ventien, the proper correctienal weight vaiueanti for the conteet e pplim'me; its true anguier point of applicationbe de- Figure '7 presents unether style at e1ectrie-eir= ten mined cuitfor the same;

The earlier art discloses methecis emmrzt- Figure 8 portrays theWheatstone-brldge sir tus for determining the high paint er paint efcult used; maximum displecement of vibration of a, retetmg Figures 5%and 10 illustrate another embecii unbalanced member as indicative at theangular ment of the invention;

paint of weight correction, but this high paint Figures 11 and 12 depictstill a. further design; will be at a new position for every diflereutvalue and of unbalance as well as for every different speed Figure 13shows another modified form oi w of rotation. I v paratus.

new upplmnee 1523 eieetricelly etw In these drawings, a conventionalbalancingmachine has been shown, such appliance including a pair ofspaced-apart, aligned, open-top bearings 22, 22 for supporting the shaft23 on which is mounted the body 24 to be tested for its balance or lackthereof, each such bearing 22 being supported from above by a pair ofwires or straps 25, 25 (Figure 2) supported at their top ends on posts26, 26 rising from a suitable base 21, such shaft 23 and its body 24being rotated by an electric-motor 28 having a pulleyand-belt connection29 with the shaft.

One such bearing 22 of the two, by means of a rod or link 3I, isoperatively connected to a substantially-upright rock-arm 32 hinged orrockingly associated therewith at, 33, such arm being mounted, on astationary extension 34 of one of the posts or standards 26, on ahinge-pin 35 from which it is suitably insulated and about the axis ofwhich it will vibrate or oscillate in conformity and harmony with thevibrato y movement of the body 24 undergoing test, this arm beingyieldingly pulled in the direction toward shaft 23 by a coiled-spring 36connected at one end to the arm 32 and at its opposite end to thestationary part 34.

Such arm 32 is provided with an outstanding electric-terminal in theform of a pin 31 with which the arm is in electrical connection, and

.a second arm 38, also hinged or rockingly supported on the hinge-pin 35and insulated from arm 32 and also from such hinge-pin, is adaptedthrough its own integral contact 30 to make electrical contact with thepart 31, being pulled in that direction by a coiled-spring 4i fastenedat one end to arm 38 and at its opposite end to a part of the fixedmember 34.

An internally and externally screw-threaded headed sleeve or part 42 isfixedly mounted in an aperture through the wall 43, constituting aportion of the member 34, by a retaining-nut 44, and the screw-threadedpassage through such sleeve accommodates a hollow screw 45 adjustablelengthwise in the sleeve by its knurled handle 46.

This screw 45 is internally screw-threaded, at least for a portion ofits length, and engaging such thread thereof is an inner screw 41turnable by its knob 48, one end of such screw 49 acting as a contact inalignment with a companion contact 5| forming part of rock-arm 38.

From what precedes, it should be clear that the metal, conductive member38 has the two contacts 30 and 5| integral therewith, so that a portionof the arm constitutes an electricallyconductive bridge joining the twocontacts.

Mounted on and rotatable with the manuallyturnablelengthwise-adjustable, hollow screw 45 is the revoluble contact arm orrotor 52 of a circular rheostat 53 carried on, and the resistancewire ofwhich is insulated from, the stationary element 42, theelectric-connection for such rotor comprising a spirally-wound,flexible, metallic strip fastened at its inner end to the screw 45, itsouter end forming a terminal 54 of the rheostat, the end of theresistance-wire of the rheostat having a companion terminal 55,

Mounted on one of the adjacent immovable standards 26 is a finger 56(Figures 1 and 2) having a pointer or index end 51 directly over and inregister with the axis of shaft 23 when the latter is not rotating, anddirectly beneath such pointer, the shaft has fixed thereto and rotatabletherewith a round or circular wheel 56 displaying on its cylindricalperiphery index or III) graduation marks, as shown in Figures 1 and 5,such marks being supplied with numerals from 0 to 9 inclusive along asemi-cylindrical portion of one edge section thereof and with numeralsfrom 10 to 19 inclusive along the opposite edge portion of the remainingsemi-circular part thereof. 9

An appropriately-shielded, stroboscopic electrio-lamp 59 is sopositioned on the frame of the machine that the light flashes issuingintermittently therefrom will adequately illuminate the circumference ofthe designated scale-member Figure 6 shows one style ofelectrical-system in which the described lamp may be used.

In such arrangement of parts, the two terminals of the lamp-circuit,including a source of electric-current, the remainder of which circuitneed not be illustrated because it is well understood in the art, aredesignated 6| and 62, such terminal 6| being connected by a wire 63 tothe frame part 43 through the terminal 64 (Figure 3) so that terminal BIis in direct electrical association with screw 41 and its contact end49.

The companion terminal 62 of the lamp-circuit is joined by wire 65 tothe movable arm 66 of an electric-switch having threestationarycomplementary contact 61, 68 and 69 with any one of which arm 66 maymake connection, such contact 69 being connected to the backwardly andforwardly swinging arm 32 by wire 1|, contact 61 being joined to thesecond arm 38 and its two contacts 5| and 39 by wire 12, theintermediate contact 68 being unconnected.

It will be apparent from the illustration of this organization, thatwhen switch-arm 66 engages switch-contact 69, the two switches 49-5I and31-30 will be in series relation, whereas, when such arm contacts withthe switch-member 41, switch 31-30 will be electrically cut out but notmechanically and the switch 49-5I only will be electrically operative,so that the two switches may be employed in series combination or thesingle switch 49-5I may be used alone.

A somewhat modified or alternative circuit arrangement, in which eitherswitch alone may be availed of, or the two switches employed in seriesmay be utilized, is presented in Figure 7.

In this case, the lamp-circuit terminal 6| is directly connected by wireI63 to the contact 64 of part 43 and through these to screw 41 and itsend terminal 49, and the complementary lampcircuit terminal 62 isdirectly joined to arm 32 and its contact 31 by wire I64, while wire I12connects arm 38 and its twocontacts 5i and 39 with the movableswitch-arm "I, the three stationary contacts of the switch beingcharacterized I65, joined to wire I63 by connection I68; I66 notconnected to anything; and I69 connected to wire I64 by connection I61.

Manifestly, when switch-arm I1I engages switch-contact I66, bothswitches 49-5I and 31-36 are operative and in series with one another;when arm I1I touches switch-contact I65, switch 49-5I is short-circuitedand hence electrically inoperative with switch 31-39 in operation bothelectrically and mechanically; and

when part I' II abuts switch-contact I69, switch 31-30 is out of actionelectrically but not mechanically, switch 49-5I alone being inoperation.

Figure 8 portrays the Wheatstone-bridge electrical-system employedincluding the alreadymentioned, variable resistance 53 as a part of onearm ofthe system, the remainder of such arm constituting a fixedresistance IS, the co panion arm of the system being resistance 14, theresistances of the two other correlated arms being designated as 15 and18.

As is iully illustrated in Figure 8 of the drawlugs, the usual batteryor other suitable source,

oil electric-current l1 and its participating ad- ;lustablc resistanceIt are, as customary, connected in series relation across thebridge-clrcult from between the resistances 15 and"; to the connectionbetween the resistances 13 and i l, and, as, usual, theelectric-galvanometer 19, or its equivalent, i joined to the systembetween the resistances 53 and i and between the resistances id and lit.

' When the electric-current supplied by the battery is flowing throughthese resistances, the two 53 and it being considered as a variable one,and the several resistances are balanced, there is no tcntial diiferenceimposed on the two tersis of the galvanometer and its needle remainsstationary; on the other hand, however, if the resistance of therheostat 58 is changed, the system becomes unbalanced, a currentcorresponding in strength to the resistance change flows through thegalvanzmieter and its needle is correspondingly deflected to afford acomparable Assuming that the novel appliance of this invention is beingactuated by rod 3i, so that arm rocked forwardly and rearwardly inconsonance with, and proportionately to, the vibratory movement of therotating body 2d undergoeiralnination as to its balance and of itssupporting members, it will be seen and 3t, insulated from one another,are pivoted at the same point 5135, they will be vibrated together as aunit, and, with screw 41 adjusted so that it contact end it will remainentirely out of contact with its companion oscillating contact Eli,contact EU will be constantly'in physical and electrical engagement withthe outstanding contact-pin ill" on arm 32, regardless oi theoscillatmovements of both arms.

"By adjusting contact it by its, screw 4'! toward the pair ofoscillating arms t2 and 3t sufliciently, contacts ill and iii could becaused to remain conuously in engagement with one another reless oi theswinging and reciting movement f it, and contacts and Eli would beconstantly out of engagement with one another.

lllearly then a point of adjustment of contact il may be readily foundsuch that there will be a substantially-simultaneous,practically-instant neous closure of one pair of contacts and separationof the other pair of contacts caused by the oscillation of the arms.

Accordingly, if an electric-circuit, such as that the stroboscopic-lamp,be connected to contests 45% and 55 through contacts ill and 30, therewill be two substantialiydnstantaneous or momentary closures of thecircuit for each cycle of oscillation, one very short closure when con--tact 19 engages contact at and the circuit is broken immediately atcontacts and 30. and another similar closure during the return part thecycle and movement of the elements involved when contact is made betweenparts 38 and 3? and the circuit is broken instanter bycontact 5! leavingcontact 49.

With the circuit of the stroboscopic-lamp thus connected, the light willflash once for each such extremely-short closure of its circuit eifectedas described by the action of the two cooperating switches, and theseintermittent light flashes that, since arms 3 will illuminate thegraduations of the element t8 revolving with the rotatingbody undertest, the light supplying two flashes for each revolution each completecycle of oscillation caused by the unbalance of such body. g

One such flash occurs when the revolving body passes the pointer 51 inone direction of its vibration and the other flash takes place as suchbody passes the pointer while the vibrating body is traveling in theopposite direction.

It, therefore, the contact id is adjusted by its screw so that theoperator, during the two alterhating sets of flashes, sees two numberssimultaneously side by side on the wheel 58, which are ill units apart,as for example 7 and 17, that indicates that the center plane ofoscillation or vibration of the body is that which passes through suchtwo numbers, andthis can be readily noted on the body undergoing testafter its rotation has been stopped. J

In this connection, it should be remembered that since the wheel ormember 53 has 20 numerals around its 360 periphery thereof any twonumerals thereon with a difl'erence of -10 are necessarily 180 apart ordirectly opposite one another.

Thus the two flashes occur 189 apart, so far as the body examined isconcerned, each taking place at the instant the center of vibrationregisters with the pointer. I

Now by changing the electrical connections, as shown, in either Figure 6or Figure 7, whichever is employed, by means of switch-arm 66 or "I, oneflash can be terminated leaving the other flash in action to illuminateone only of the two numerals and this will indicate theangular positionoi the body when it is passing the centerofwibratlon in one direction,such direction depending upon which flash has been selected to remainoperative.

It is necessary to ascertain how much weight should be added to orsubtracted from the body to balance it and that is accomplished in thefollowing manner:

Viihile the parts are rotating and the one set of flashes areilluminating the single index, as for example-7, the operator adjuststhe outer or external screw by its knurled knob 85 and therebysimultaneously and equally adjusts the inner screw ll and its contact 49until he sees the next number 6 or 8 at the pointer 5? by means of theseries of intermittent light flashes.

Such numeral 6 or 8 thus presented to view shows that the rotating bodyhas been revolved 18 from the central point of vibration and the extentof turning the screw is proportional to the part of the vibratorymovement of the body necessary to eiTect this change in numerals seenand is commensurate with the total amplitude of vibration of the bodywhich, at the speed of rotation employed, is proportionate to theunbalance in the body.

As will be readily understood, such turning of the screw lzl andswitchwontact 29 causes the rheostat rotor-arm 52 to vary the resistanceoi the rheostat proportionally to the adjustment travel of the contact,that is proportional to the amount of vibration travel during 18 ofrotatic-n of the unbalanced body, and the galvanometei needle iscorrespondingly influenced to afford a comparable reading.

Therefore, with the known pitch of the screwthread of screw 15 and theknown electrical resistance measuring circuit already described, the

of such body, that is to say, two flashes tor galvanometer may becalibrated in exact linear indications of the amplitude of oscillationor it may be calibrated in other suitable units, such as the weight ofcorrectional material for addition to or removal from the unbalancedbody undergoing examination.

With the various data supplied by the tests presented above, the bodymay be easily modified to render it suitably balanced.

Obviously, instead of making the contact adjustment such as to displaythe next single numeral of the graduated-scale, it may be moved to causea showing of some other number, provided the galvanometer-graduationsare made to correspond to such change of procedure.

In order to hold screw 45 in normal or neutral position with therheostat contact-arm 52 in its unoperated relation a stop i8! on thescrew may engage a fixed stop i82 on member 42 to limit turnin of thescrew in one direction.

For the ascertainment of the center of oscillation of the unbalancedrotating body, other alternative structures may be employed, in whichinstances the graduated-wheel 58 is not needed.

One such substitute structure is presented in Figures 9 and 10 and itincludes a disc 8! mounted on a reduced-diameter end portion of shaft 23to revolve with the body 24 undergoing test, such disc having a visible,radially-disposed arrow 82 on its outer face reaching from the center ofthe disc to or approximately to its periphery.

A rockably-mounted, lengthwise-shiftable, manually-adjustable pointer 83mounted on a stationary part of the appliance is of such extent that itsactive end can be brought to, and maintained at, any position adjacentto any portion of the periphery of the disc.

The stroboscopic-lamp I59 is located so that it will illuminate thearrow-equipped, outer surface of the disc, the lamp otherwise operatingas hereinabove fully set forth.

As in the previous instance, the contact-adjusting screw 41 is turneduntil alternate flashes of the lamp show the successive illuminations ofthe arrow in direct alignment with one another, that is as a singlestraight line, extended across the full diameter of the disc whichassures that at those two instants the body 24 is passing itscenter-of-vibration in its two opposite directions of travel.

After the operator views such double-length, rectilinear line, composedof the two arrow images, he, as indicated above, terminates one seriesof such light flashes so that he then perceives but a single-lengtharrow, whereupon he adjusts the pointer angularly and lengthwise to haveits end coincide with the outer end of such arrow.

Then when the rotation of the parts is stopped, and they are turned tobring the outer end of the arrow into register with the operative end ofthe pointer, it will be known that the angular position of the body whenpassing through the center-of-oscillation in one direction is thatindicated by the arrow and pointer.

A different structure, without the lamp, may be used as shown in Figures11 and 12 in which case the disc 84, instead of disc 8i, is used on theend of the shaft 23, such round member being of insulating-materialhaving a narrow, conductive collector-ring 85 mounted on its back face,a conductive, pointed terminal 85 (Figure 11) mounted on aninsulation-block 81 on the bearing-member 22 being close to ring 85andproviding a short spark-gap between itself and the ring, a wire 88being connected to such terminal 88' and another wire being joineddirectly to the metal part 22.

Disc 84 has a radial aperture 89 through it and in, or in register with,this space are two terminals 9| and 82 spaced apart to afford a sparkgapbetween them, such terminal 9| being electrically connected to thecollector-ring 85 and the companion terminal 82 being electricallyconnected by a wire 83 to shaft 23 and through the latter and member 22to wire 88.

Thus this construction comprises a portion of an electric-circuitbetween conductors 88 and 88, including two spark-gaps in seriesrelation.

Assuming that such partial, two-gap circuit is substituted for the lamp,during each revolution of the shaft and its unbalanced body subjected totest, the operator facing the disc will see two series of sparks and byadjustment of screw 41 and its contact 49, he can cause such sparks tooccur apart so that the two series of radial sparks will appear to be inalignment with one another.

Then by changing th electric-circuit so that only one such series ofsparks is seen, the operator manually adjusts pointer 83 to bring itinto register with such sparks, and thereafter, after the rotation hasceased, the shaft and body are turned to register the spark-gap with theend of the pointer, with a comparable result as indicated above withrespect to arrow 82.

Instead of the use of a spark-gap for this purpose, a glow-tube 94, suchas a neon-tube, may be used in a somewhat-longer, radial window 85 in adisc 98, the construction and mode of operation being otherwise asindicated above, in connection with the spark-gap.

As will be readily understood, full round discs are not essential,single radial arms being capable of employment in their stead in thatthe greater portions of the discs perform no useful function.

We claim:

1. In-an appliance, for use with a balancetesting machine includingmeans to support the body to be tested in a manner permitting itsrotation about its axis and having freedom of movement in both lateraland longitudinal horizontal directions .by reason of its unbalance, andmeans to rotate said body about its axis, said appliance havingindex-means including an electric lightflash means, an electric-circuitadapted to be supplied with electric-current and including saidlight-flash means, electric-switch means in said circuit, and meansactuated by the vibration of said rotating body operating saidelectric-switch means and thereby governing said light-flashes, thenovel combination of features being that said electric-switch meanscomprises two electricswitches in series relation in said circuit, incombination with (a) means to adjust the action of said switches so thatwhen the rotating body passes its center-of-oscillation in onedirection, one said switch closes said circuit and the second switchimmediately opens the circuit, such action producing a light-flash, andwhen the body passes said center-of-oscillation in the oppositedirection, said second switch closes said circuitand said first switchimmediately opens the circuit, said action producing a light-flash at180 difference in rotation of the body from said first flash, (b) meansto eliminate one set of said lightflashes, and (c) a pointer adapted tocooperate with said index-means, said pointer and said index-means beingadjustable relatively to one another.

2. The novel combination of features set forth in claim 1, including theadditional features that said index-means includes a round memberrotatable with said body and having on its periphery two sets ofindices, one set extending around 180 of such periphery and the otherset around the remaining 180 of such periphery, and that said electriclight-flash means is a stroboscopiclight in said electric-circuitilluminating said indices intermittently, said pointer cooperating withsaid indices, whereby the center-of oscillation of the body undergoingtest is indicated when two of said indices 180 apart are viewedseeminglysimultaneously at the pointer by the operator.

3. The novel combination of features as set forth in claim 1, includingthe additional novel features that said index-means includes a' discrotatable with said body and displaying a radial mark, and that saidelectric light-flash means is a stroboscopic-light in saidelectric-circuit intermittently illuminating said mark during itsrotation, whereby the center-of-oscillation of the body undergoing testis indicated when the operator sees such mark on opposite sides of theaxis of rotation and as of straight double length, the adjustment ofsaid pointer permitting it to be brought into register with said markduring its rotation while illuminated by one set of said lightflashes.

4. The novel combination of features as set forth in claim 1, includingthe additional novel features that said index-means includes a memberrotatable with said body and that said electric light-flash means insaid electric-circuit is mounted on said member radial to the axis ofrotation of said body and member, whereby the center-of-oscillation ofsaid body is indicated when the operator during the double series oflight-flashes sees the light-flash means at two positions directlyopposite one another on opposite sides of said axis, the adjustment ofsaid pointer permitting it to be brought into register with saidelectric light-flash means during the rotation of the latter whileilluminated by one set of said light-flashes.

5. In an appliance, for use with a balancetesting machine includingmeans to support the body to be tested in a manner permitting itsrotation about its axis and with freedom of movement in both lateral andlongitudinal horizontal directions by reason of its unbalance, and meansto rotate said body about its axis, said appliance having index-meansincluding an electric lightfiash means, an electric-circuit adapted tobe supplied with electric-current and including said light-flash means,electric-switch means in said circuit, and means, actuated by thevibration of said rotating body, operating said electric-switch meansand thereby governing said light-flashes, the novel combination offeatures being (a) that said electric-switch means comprises twoelectricswitches in series relation in said circuit, (b) that saidindex-means includes a round member rotatable with said body and havingon its periphery two sets of indices, one set extending around of suchperiphery and the other set around the remaining 180 of such periphery,(c) that said electric light-flash means is a stroboscopiclamp in saidelectric-circuit producing said lightflashes illuminating said sets ofindices intermittently, (11) means to adjust the acton of saidelectric-switches so that when the rotating body passes its centerd-oscillation in one direction, one said switch closes said circuit andthe second switch immediately opens the circuit, such action producing alight-flash by said stroboscopic-lamp, and when the body passes saidcenter-of-oscillation in the opposite direction, said second switchcloses said circuit and said first switch immediately opens the circuit,such action producing a light-flash at 180 difference in rotation of thebody from said first flash, (e) means to eliminate one set of saidlight-flashes, (f) a pointer adapted to cooperate with said sets ofindices, (y) means to adjust the action of said electric-switches whenone set only of said indices is illuminated by said light-flashes tochange their operation so that another index of such set is illuminated,and

(h) an indicator operated in proportion to the extent of movement ofsaid adjusting means set forth in (g), whereby said indicator shows theequivalent of the vibration-amplitude of the body undergoing test.

IRA A. WEAVER. CLYDE H. PHELPS.

